worker.md

• Worker (class)
  • Worker (constructor)
  • Worker.initialData (static StructuredClonable property)
  • Worker.parent (static object property)
  • Worker.prototype.postMessage (method)
  • Worker.prototype.onmessage (property)
  • Worker.prototype.onerror (property)
  • Worker.prototype.terminate (method)
• StructuredClonable (type)

Worker (class)

Workers can be used for multi-threaded, concurrent work.

YavaScript's global Worker class is a subclass of the QuickJS's os.Worker which loads all of the YavaScript API globals into the Worker's global context.

It behaves similar to Web Workers.

declare class Worker {
  constructor(
    moduleFilename: string,
    options?: {
      overrideCode?: string;
      initialData?: StructuredClonable;
    },
  );
  static initialData: StructuredClonable;
  static parent: {
    postMessage(msg: StructuredClonable): void;
    onmessage: null | ((event: { data: StructuredClonable }) => void);
  };
  postMessage(msg: StructuredClonable): void;
  onmessage: null | ((event: { data: StructuredClonable }) => void);
  onerror:
    | null
    | ((event: {
        message: string;
        filename: string;
        lineno: number;
        error: Error | null;
      }) => void);
  terminate(): void;
}

Worker (constructor)

Create a Worker which runs the module at moduleFilename.

If options.overrideCode is present, the Worker instead runs a synthetic module with filename moduleFilename and source code options.overrideCode (JS source code string). In this case, moduleFilename is not read from disk and is only used as the module's assigned filename for import.meta, module resolution, etc.

If options.initialData is present, it'll be available within the worker as the static initialData property on the Worker constructor.

constructor(moduleFilename: string, options?: {
  overrideCode?: string;
  initialData?: StructuredClonable;
});

Worker.initialData (static StructuredClonable property)

If accessed within a Worker, and the Worker was constructed with non-undefined initialData, then this will be a structured clone of that initial data.

Outside of a worker, this is always undefined.

static initialData: StructuredClonable;

Worker.parent (static object property)

Worker-side communication channel back to the parent context that invoked it (ie. the main thread).

static parent: {
  postMessage(msg: StructuredClonable): void;
  onmessage: null | ((event: {
    data: StructuredClonable;
  }) => void);
};

Worker.prototype.postMessage (method)

Send a message from the main thread to the worker.

postMessage(msg: StructuredClonable): void;

Worker.prototype.onmessage (property)

This function is called when a message arrives from the Worker. You may override this property with your own function.

onmessage: null | ((event: {
  data: StructuredClonable;
}) => void);

Worker.prototype.onerror (property)

If an unhandled Error is thrown in the Worker or an unhandled Promise is rejected in the worker, this onerror function will be run.

When onerror is unset, errors print to stderr.

onerror: null | ((event: {
  message: string;
  filename: string;
  lineno: number;
  error: Error | null;
}) => void);

Worker.prototype.terminate (method)

Terminate the worker thread. Equivalent to setting onmessage to null.

terminate(): void;

StructuredClonable (type)

Types which can be sent to/from Workers.

declare type StructuredClonable =
  | string
  | number
  | boolean
  | null
  | undefined
  | Boolean
  | String
  | Date
  | RegExp
  | ArrayBuffer
  | Int8Array
  | Uint8Array
  | Uint8ClampedArray
  | Int16Array
  | Uint16Array
  | Int32Array
  | Uint32Array
  | Float32Array
  | Float64Array
  | BigInt64Array
  | BigUint64Array
  | DataView
  | Array<StructuredClonable>
  | SharedArrayBuffer
  | {
      [key: string | number]: StructuredClonable;
    };